The present invention relates to valves, and in particular, to a pneumatically actuated valve that uses a pitot tube.
In many gas turbine engines, a bleed system is used that bleeds gas off a compressor section to be used for various purposes. Such bleed systems typically have one or more valves that control flow of gas through the bleed system. Some valves include a pitot tube positioned on an upstream side of the valve and operate using air from the pitot tube. When the valve detects a downstream pressure that is beyond a threshold, pitot tube air is used to partially close the valve to reduce pressure downstream of the valve. Alternatively when the downstream pressure is below a threshold, pitot tube air is used to partially open the valve to increase pressure downstream of the valve.
Gas bled from a compressor section typically includes various particles, such as engine oil, in addition to air. Such particles can pass through a pitot tube and undesirably contaminate internal systems of the valve, such as its torque motor or solenoid, filter, seal rings, and/or flow passages. If enough contaminating particles enter the pitot tube, the resulting contamination can cause the bleed valve to fail, requiring time-consuming and expensive repair or replacement of the torque motor and/or the entire valve.